Baseline elevated leukocyte count in peripheral blood is associated with poor survival in patients with advanced non-small cell lung cancer: a prognostic model

Abstract

We aimed to investigate the prognostic significance of several baseline variables in stage IIIB-IV non-small cell lung cancer to create a model based on independent prognostic factors. A total of 320 patients were treated with last generation chemotherapy regimens. The majority of patients received treatment with cisplatin + gemcitabine or gemcitabine alone if older than 70 years or with an ECOG performance status (PS) = 2. Performance status of 2, squamous histology, number of metastatic sites >2, presence of bone, brain, liver and contralateral lung metastases and elevated leukocyte count in peripheral blood were all statistically significant prognostic factors in univariate analyses whereas the other tested variables (sex, stage, age, presence of adrenal gland and skin metastases) were not. Subsequently, a multivariate Cox's regression analysis identified PS 2 (P < 0.001, hazard ratio 2.57), elevated leukocyte count (P < 0.001, hazard ratio 1.79), squamous histology (P = 0.005, hazard ratio 1.45) and presence of brain metastases (P = 0.035, hazard ratio 1.5) as independent prognostic factors for poor survival. Patients were assigned to one of three risk groups according to the cumulative risk defined as the sum of simplified risk scores of the four independent prognostic factors. Low-, intermediate- and high-risk patients achieved a median survival of 10.2 months (95% confidence interval (CI) 8.9-11.6), 5.1 months (95% CI 4.0-6.2) and 2.8 months (95% CI 0.5-5.2), respectively. The high-risk group encompassed PS 2 patients with two or three adjunctive unfavourable independent prognostic factors. Performance status, white blood cells count, histology and brain metastases resulted in our series prognostic factors of survival in NSCLC patients treated with chemotherapy at a multivariate analysis. Leukocyte count resulted the stronger factor after performance status. If prospectly validated, the proposed prognostic model could be useful to stratify performance status 2 patients in specific future trials.